Method of and apparatus for maintaining dielectric properties of a nonconductive medium



Jan. 29, 1935. E. MENDENHALL ET AL METHOD OF AND APPARATUS FORMAINTAINING DIELECTRIC PROPERTIES OF A NONCONDUCTIVE MEDIUM Filed Oct.10, 1931 N/MLL u/v/as 5 V4 A /V,

yIlIll Il Iii Patented Jan. 29, 1935 UNITED STATES PATENT OFFICE EarlMendenhall and Junius B. Van Horn, Los Angeles, Calii., assignors toMenhorn, Inc., Los

Angeles, Calif., a corporation of California Application October 10,1931, Serial No. 568,192

13Claims.

Our invention relates to a method of and apparatus for maintaining thedielectric properties of a non-conductive medium, and is particularlyapplicable to oils employed with electrical apparatus which is eithersubmerged or in an inaccessible position.

In motors containing oil and placed in an inaccessible position orsubmerged, as in a well, any particles of moisture which become mixedwith the oil tend to diminish the dielectric strength of the oil and toimpair the efiiciency of the electrical apparatus. It is a correspondingpurpose of our invention to provide a method of and apparatus forremoving particles of water from the oil in which such an electricalapparatus is submerged.

Inasmuch as the space occupied by electrical apparatus disposed in awell must be kept to a minimum, it is a purpose of our invention toprovide a method of maintaining the dielectric properties of oil whichrequires only such apparatus as may be contained in an extremely smallspace.

More particularly, it is a purpose of our invention to provide anapparatus for maintaining the dielectric properties of oil whichincludes the positioning of a hygroscopic medium in contact with theoil.

Our method of maintaining the dielectric property of oil contemplatesthe positioning of a body of material having an afllnity for water incontact with the oil, and the circulation of the oil relative thereto.

In the drawing, which comprises a vertical cross-sectional view of theapparatus of our invention, in order to illustrate the advantages andutility of our invention, we have shownthe particular embodiment of ourinvention which is adapted for use with electrical motors disposedadjacent the bottom of a well for operating a pump.

Referring to the drawing, which is for illustrative purposes only, thenumeral 11 indicates a cylindrical casing positioned near the lower endof a well 12. Contained in the upper portion of the casing 11 is anelectrical motor 13 which includes a stator 14 and a rotor 15, the rotor15 being non-rotatably secured to a vertical shaft 16. The lower end ofthe shaft 16 is supported in a journal member 17 attached as by arms 18to the inner surface of the casing 11. Disposed above the motor 13 is asecond journal member 20 surrounding the shaft 16 and supported by arms21 attached to the inner surface of the casing 11.

Positioned in the casing 11 above the journal is adapted for rotationwithin an impeller bowl 28.

so that upon rotation of the impellers liquid is forced from theimpeller bowls 28 upwardly through an outlet pipe 29 in a manner wellknown in the art. The fluid thus pumped is drawn from the exterior ofthe casing 11 through openings 30 provided in the casing 11 above thetop member 22.

Attached to the casing 11 below the journal member 17 is a battle member31 having openings 32 therein, this baiile member dividing the interiorof the casing 11 into a motor chamber thereabove and a balance chambertherebelow. The lower end of the casing 11 may be closed ofi as by anend member 33, the interior of the casing 11 communicating with theexterior thereof through an opening 34 adjacent the end member 33. Ifthat portion of the casing 11 between the top member 22 and the endmember 33 be substantially filled with oil of high dielectricstrength,and the unit thus described be disposed in a well and submerged in wateror a liquid containing water, this liquid enters through the openings 34in the casing and exerts upon the oil contained within the casing 11 anupward pressure equal to the downward pressure exerted by the liquidentering the casing 11 through the openings 30 above the top member 22.The pressure on the lower side of the packing is thus made substantiallyequal to the pressure on the upper side of the packing so that thetendency for the liquid above the top member 22 to enter through thepacking member 25 and mix with the oil within the casing 11 ispractically eliminated. The fluid from thevexterior of the casing 11which enters through the openings 34 assumes a quiescent level indicatedby the numeral 35'representing the surface of contact of the twoliquids. It should be evident that a considerable volume of the oil mayescape from the casing 11 before the level 35 of the fluid containingwater has approached near enough to the motor 13 to become dangerous.

However, some of the particles of water from below the level 35 maybecome mixed with the oil contained within the casing 11. Likewise, someparticles of water may enter this oil through the packing 25 or anysmall leak in the casing 11. Similarly, there may be present in thecasing 11 particles of water which were present in the casing 11 whenthe casing was filled with oil, or which condense on the walls of thecasing during the filling of the casing. To remove these particles ofwater from the oil contained within the casing 11, we provide upon theupper surface of the bafile member 31 a container 36 which may be in theform of a closely woven scr'een. Retained in the container 36 is a bodyof material 37 having hygroscopic properties. This material may becalcium chloride, plaster of Paris, trade compounds such as Silica-Gel,cements, or any such medium having an afiinity for water. The oil withinthe casing 11 being circulated by the rotation of the rotor 15, anyparticles of water contained therein are brought soon aftertheirentrance into the oil into contact with the body of material 37and, because of the hygroscopic nature of the material 37, theseparticles of water are thus removed from the oil contained within thecasing 11.

By providing the bafiie member 31 with the openings 32, the fluid fromthe exterior of the casing 11 which enters the casing 11 through theopenings 34 is permitted to exert upon the oil within the casing 11above the baffle member 31 a pressure equal-to the pressure on theexterior of the casing 11. However, since the communication between thatportion of the interior of the casing above the'baflie member 31 andthat portion of the interior of the casing below the baflie member isaccomplished only through the openings 32, the circulation of oil causedby the rotation of the rotor 15 is prevented from creating a sufiicientturbulence of the oil below the baflle member 31 to cause anagitationwhich would allow a harmful amount of the water enteringthrough the openings 34' to become mixed with the oil in the casing 11.The relative proportion of the hygroscopic material 37 and the oilcontained within the casing 11 may be varied to provide for the needsoccasioned by the type of electrical apparatus employed and theconditions under which it is used.

In order to illustrate the utility of our invention we have referred tothe conductive medium as water, and the non-conductive medium as oil. Wewish it understood that these media have been referred to forillustrative purposes only, and that our invention includes the use ofother conductive and non-conductive media as well.

While that embodiment of our invention hereinbefore illustrated anddescribed is fully capable of performing the objects and providing theadvantages primarily stated, there are other embodiments of ourinvention likewise capable of performing these objects and providingthese advantages, and we therefore wish our invention to be understoodas not restricted to the specific embodiment hereinbefore set forth.

We claim as our invention:

1. The method of drying an oil of high dielectric strength andpositioned around an electric motor which includes the positioning of abody of hygroscopic material therein and circulating said oil relativeto said body and in'cooling relationship with said motor.

2. A method of maintaining the dielectric properties of a dielectric oilaround an electric motor and having access to a conducting liquid, whichmethod includes the steps of: positioning in said oil a body of materialhaving an affinity for said conducting liquid; circulating saiddielectric oil in cooling relationship with said motor adjacent saidbody of material whereby any of said conducting liquid entering said oilbecomes associated with said body of material; and retaining said bodyof material and its associated conducting material in fixed position toprevent any of said material and its associated conducting liquid frombeing dispersed in said dielectric liquid.

3. A method of maintaining the dielectric properties of a dielectric oilaround an electric motor and in surface contact with a conductingliquid, which method includes the steps of: retaining a body ofhygroscopic material in fixed position in said body of dielectric oil;and circulating said dielectric oil to move same into contact with saidbody of hygroscopic materialand in cooling relationship with said motor.

4. A method as defined in claim 3 in which said body of hygroscopicmaterial is positioned insaid dielectric oil in spaced relationship withthe surface of contact between said dielectric oil and said conductingliquid, and including the step of shielding the surface of contact fromthe stream of dielectric oil thus circulated in cooling relationshipwith said motor to prevent agitation at said surface of contact whichwould cause additional intermixture.

5. In combination in a submersible electric motor: a casing surroundedby a conducting liquid and containing a body of dielectric liquid havingaccess to said conducting liquid whereby minute particles of saidconducting liquid may become associated with said dielectric liquid; ashaft extending through said casing to a point exterior thereof; sealingmeans at the junction of said shaft and said casing; means for rotatingsaid shaft and circulating said dielectric liquid, said means includingan electric motor positioned in said dielectric liquid; and a. mass ofhygroscopic material having an affinity for said conducting liquid andpositioned in said casing and in the path through which said dielectricliquid is circulated.

.6. A combination defined in claim 5 including an interstitial containerpositioned in the path through which said dielectric liquid iscirculated and containing said mass of hygroscopic material.

7. In combination in a submersible electric motor: a casing surroundedby a conducting liquid and containing a body thereof, said casing alsocontaininga body of dielectric liquid in surface contact with said bodyof conducting liquid; an electric motor positioned in said body ofdielectric liquid; and a mass of hygroscopic material positioned betweensaid motor and the surface of contact of said bodies of said dielectricliquid and conducting liquid and having an affinity for said conductingliquid to. remove from said dielectric liquid any of said conductingliquid entering therein before the contaminated dielectric liquid movesinto contact with said motor.

8. In combination in a submersible electric motor: a casing positionedin a conducting liquid and containing a dielectric liquid; baflie meansin said casing and dividing the interior thereof into a motor chamberand a balance chamber, said bal ance chamber containing contactingbodies of said conducting liquid and said dielectric liquid, said bafllemeans defining an opening through which said motor chamber and saidbalance chamber are in communication with each other; a shaft extendingfrom'said casing; means for rotating said shaft and circulating saiddielectric liquid in said motor chamber, said means including anelectric motor driving said shaft, said bailie means preventing thecirculation of said dielectric liquid which takes place in said motorchamber from agitating said contacting bodies of said liquids in saidbalance chamber; and means retaining a mass of hygroscopic material insaid body oi dielectric liquid in the path of movement 01' saiddielectric liquid, said hygroscopic material having an amnity for saidconducting liquid.

9. A combination as defined in claim 8 in which said last-named meansincludes a container in said motor chamber and positioned in the path 01the dielectric liquid circulating in said motor chamber and including amass of hygroscopic material retained in said container and having anaflinity for said conducting liquid.

10. A method of maintaining the dielectric properties of a dielectricoil positioned in a motor shell containing a motor and having access toa conducting liquid, which method includes the steps of: submerging saidmotor shell in said conducting liquid; positioning in said motor shell a.body of a material having an aflinity for said conducting liquid; andcirculating said dielectric oil "1 a closed circulation path duringwhich flow said oil moves adjacent said motor in cooling relationshiptherewith and adjacent said body of material whereby any of saidconducting liquid entering said oil becomes associated with said body 0!material and is thereby kept from reaching said motor.

11. A method of maintaining the dielectric properties of a dielectricoil positioned in a motor shell containing a motor and having access toa conducting liquid, which method includes the steps of: submerging saidmotor shell in said conducting liquid; positioning in said motor shell abody of a material having an amnity for said conducting liquid;circulating said dielectric oil in a closed circulation path duringwhich flow said oil moves adjacent said motor and adjacent said body ofmaterial whereby any of said conducting liquid entering said oil becomesassociated with said body of material and is thereby kept from reachingsaid motor; and retaining said body of material and its associatedconducting material in fixed position to prevent any of said materialand its associated conducting liquid from being dispersed in saiddielectric liquid and reaching the working parts of said motor.

12. In combination in a submersible electric motor: a casing containinga dielectric liquid and submerged in a conducting liquid of higherelectric conductivity than said dielectric liquid; an electric motor insaid casing and including a rotor and a stator; a shaft operativelyconnected to said rotor and extending from said casing; a semieifectiveseal at the junction of said shaft and said casing and providing endportions respectively communicating with said dielectric liquid and saidconducting liquid, a movement of said shaft forming an intermixture ofsaid liquids at said seal; and means in said casing for removing fromsaid intermixture said conducting liquid, said means returning thepurified dielectric liquid of said intermixture to said dielectricliquid in said casing.

13. In combination in a submersible electric motor: a casing containinga dielectric liquid and submerged in a conducting liquid of higherelectric conductivity than said dielectric liquid; an electric motor insaid casing and including a rotor and a stator; a shaft operativelyconnected to said rotor and extending from said casing; a semiefl'ectiveseal at the junction of said shaft and said casing and providing endportions respectively communicating with said dielectric liquid and saidconducting liquid, a movement of said shaft forming an intermixture ofsaid liquids at said seal; and means in said casing for removing fromsaid intermixture said conducting liquid, said means returning thepurified dielectric liquid of said intermixture to said dielectricliquid in said casing,

.said means including a body of material having an afllnity for saidconducting liquid, the rotation of said rotor circulating saidintermixture into the vicinity of said body of material.

EARL MENDENHALL. JUNIUS B. VAN HORN.

